fix(historian): respect gateway ceilings and history value contracts

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/OtOpcUaNodeManager.cs

@@ -5129,6 +5129,7 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
 
             RunBounded(work, HistoryReadBatchParallelism);
         });
+        NormalizeHistoryValues(nodesToProcess, results);
     }
 
     /// <inheritdoc />
@@ -5225,6 +5226,7 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
 
             RunBounded(work, HistoryReadBatchParallelism);
         });
+        NormalizeHistoryValues(nodesToProcess, results);
     }
 
     /// <inheritdoc />
@@ -5516,8 +5518,8 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
             // One node's backend failure must not throw out of the batch — surface Bad for THIS node
             // only. Logged via the injected ILogger.
             _logger.LogError(ex, "OtOpcUaNodeManager: HistoryReadEvents failed for node {NodeId}", handle.NodeId);
-            errors[handle.Index] = StatusCodes.BadHistoryOperationUnsupported;
-            results[handle.Index] = new SdkHistoryReadResult { StatusCode = StatusCodes.BadHistoryOperationUnsupported };
+            errors[handle.Index] = HistoryReadFailureStatus(ex);
+            results[handle.Index] = new SdkHistoryReadResult { StatusCode = HistoryReadFailureStatus(ex) };
         }
     }
 
@@ -6233,7 +6235,8 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
             // Bad status for THIS node only. Logged through the injected ILogger
             // rather than swallowed silently.
             _logger.LogError(ex, "OtOpcUaNodeManager: HistoryRead failed for node {NodeId}", handle.NodeId);
-            errors[handle.Index] = StatusCodes.BadHistoryOperationUnsupported;
+            errors[handle.Index] = HistoryReadFailureStatus(ex);
+            results[handle.Index] = new SdkHistoryReadResult { StatusCode = HistoryReadFailureStatus(ex) };
         }
     }
 
@@ -6722,7 +6725,8 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
         {
             // One node's backend failure must not throw out of the batch — Bad for THIS node only.
             _logger.LogError(ex, "OtOpcUaNodeManager: HistoryReadRaw (paged) failed for node {NodeId}", handle.NodeId);
-            errors[handle.Index] = StatusCodes.BadHistoryOperationUnsupported;
+            errors[handle.Index] = HistoryReadFailureStatus(ex);
+            results[handle.Index] = new SdkHistoryReadResult { StatusCode = HistoryReadFailureStatus(ex) };
         }
     }
 
@@ -6829,8 +6833,8 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
         catch (Exception ex)
         {
             _logger.LogError(ex, "OtOpcUaNodeManager: HistoryRead (modified) failed for node {NodeId}", handle.NodeId);
-            errors[handle.Index] = StatusCodes.BadHistoryOperationUnsupported;
-            results[handle.Index] = new SdkHistoryReadResult { StatusCode = StatusCodes.BadHistoryOperationUnsupported };
+            errors[handle.Index] = HistoryReadFailureStatus(ex);
+            results[handle.Index] = new SdkHistoryReadResult { StatusCode = HistoryReadFailureStatus(ex) };
         }
     }
 
@@ -6879,6 +6883,49 @@ public sealed class OtOpcUaNodeManager : CustomNodeManager2
         }
     }
 
+    /// <summary>Transport failures are retryable; unsupported operations retain their distinct status (#697).</summary>
+    private static uint HistoryReadFailureStatus(Exception error)
+    {
+        for (Exception? ex = error; ex is not null; ex = ex.InnerException)
+            if (ex is System.IO.IOException or System.Net.Sockets.SocketException or System.Net.Http.HttpRequestException or TimeoutException)
+                return StatusCodes.BadNoCommunication;
+        return StatusCodes.BadHistoryOperationUnsupported;
+    }
+
+    /// <summary>Normalize stored and AtTime history to each scalar node's declared DataType (#698).</summary>
+    private void NormalizeHistoryValues(List<NodeHandle> handles, IList<SdkHistoryReadResult> results)
+    {
+        foreach (var handle in handles)
+        {
+            if (AtTimeValueType(handle.NodeId) is not { } type || results[handle.Index]?.HistoryData is not { } body) continue;
+            var values = ExtensionObject.ToEncodeable(body) switch
+            {
+                HistoryData data => data.DataValues,
+                _ => null,
+            };
+            if (values is null) continue;
+            foreach (var value in values)
+            {
+                if (value.Value is null) continue;
+                try
+                {
+                    // A gateway number cannot reconstruct a DateTime or a String which was never stored.
+                    if ((type == TypeCode.DateTime && value.Value is not DateTime)
+                        || (type == TypeCode.String && value.Value is not string)) throw new InvalidCastException();
+                    var converted = Convert.ChangeType(value.Value, type, System.Globalization.CultureInfo.InvariantCulture);
+                    if (converted is float f && float.IsInfinity(f) && value.Value is double d && double.IsFinite(d))
+                        throw new OverflowException();
+                    value.WrappedValue = new Variant(converted);
+                }
+                catch (Exception ex) when (ex is InvalidCastException or OverflowException or FormatException)
+                {
+                    value.WrappedValue = Variant.Null;
+                    value.StatusCode = StatusCodes.BadTypeMismatch;
+                }
+            }
+        }
+    }
+
     /// <summary>Project a plain sample list into an SDK <see cref="HistoryData"/> (the paged Raw path
     /// works on a trimmed <see cref="IReadOnlyList{T}"/> rather than a whole <see cref="HistorianRead"/>).</summary>
     /// <param name="samples">The samples to project (already trimmed of boundary duplicates).</param>

src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer/ReverseRawReader.cs

@@ -100,16 +100,22 @@ internal static class ReverseRawReader
                     {
                         var asked = limit > 0 && cap > limit ? limit : cap; // cap 0 (the whole window) is never cut
                         IReadOnlyList<DataValueSnapshot> samples;
-                        try
+                        for (var attempt = 0; ; attempt++)
                         {
-                            samples = (await source.ReadRawAsync(tagname, start, end, (uint)asked, token).ConfigureAwait(false)).Samples;
-                        }
-                        catch (HistoryReadLimitExceededException ex) when (asked > 0 && ex.PreWindowRows > 0 && asked - ex.PreWindowRows >= 1)
-                        {
-                            // #694: rows just before the segment crowded the backend's budget — read it smaller; a full answer
-                            // then counts as truncated (the walk narrows), never as complete.
-                            asked -= ex.PreWindowRows;
-                            samples = (await source.ReadRawAsync(tagname, start, end, (uint)asked, token).ConfigureAwait(false)).Samples;
+                            try
+                            {
+                                samples = (await source.ReadRawAsync(tagname, start, end, (uint)asked, token).ConfigureAwait(false)).Samples;
+                                break;
+                            }
+                            catch (HistoryReadLimitExceededException ex) when (asked > 0 && ex.PreWindowRows > 0 && attempt < 2)
+                            {
+                                // #695: the discovery request may be smaller than the pre-window cluster. Size against
+                                // the ceiling, not that request; a second pass can discover more crowding rows.
+                                var ceilingRoom = source.MaxRawValuesPerRead is var learned and > 0 ? learned : asked;
+                                var smaller = Math.Min(asked - 1, ceilingRoom - ex.PreWindowRows - 1);
+                                if (smaller < 1) throw;
+                                asked = smaller;
+                            }
                         }
                         return new ForwardSegmentRead<DataValueSnapshot>(samples, asked > 0 && samples.Count >= asked);
                     },